Does anyone have any idea about the internal pressure of a, say 866 or 83 Hg-vapor rectifier, at room temperature?
Thank you in advance.
Thank you in advance.
If these are made like hot cathode Hg tubes and signs, then the internal pressure doesn't amount to more than ~1.0mmHg of carrier gas to develop heat to begin vaporizing the mercury. Hydrogen, or a mix of argon, neon, and helium gave been used for that purpose.
"Usually they have a mixture of inert gasses and I think around air pressure so 1 atmosphere".
That's way too high, even for high pressure mercury arcs. Those have ~20cmHg carrier gas fills (about 0.5atm).
According to Mercury Arc Power Rectifiers by Marti and Winograd, ". . . one condition of successful operation of mercury arc rectifiers is the maintainance of a good vacuum in the cylinder, of the magnitude of 1/100 to 1/1,000 mm mercury column, which is almost 1/1,000,000 the pressure of the atmosphere . . . . "
An interesting read about the internal function in a Wikipedia article here.
An interesting read about the internal function in a Wikipedia article here.
The temperature pressure must be kept at a range sufficient to allow for both liquid, and gaseous mercury to exist at the same time. Mercury boils at 357C or 674F at 1 ATM of pressure.
Small tubes like the 866A operate at near vacuum allowing for a good portion of the mercury to exist in gaseous form when the tube is cold. This gives a relatively quick warm up.
Huge mercury rectifiers, say to operate a subway system are often housed in large steel tanks with a heater for each pool of mercury. These tubes often require both heating and cooling systems. The heaters at the cathodes vaporize mercury, while cool spots near the top of the tube condense it and return it to the pool. Some of these require almost a day to start up.
There was a large (about 3 feet tall) all glass mercury rectifier and several medium sized tubes in a lot of 100,000 tubes that I got about 12 years ago, but I gave them all away as soon as I found those.
Small tubes like the 866A operate at near vacuum allowing for a good portion of the mercury to exist in gaseous form when the tube is cold. This gives a relatively quick warm up.
Huge mercury rectifiers, say to operate a subway system are often housed in large steel tanks with a heater for each pool of mercury. These tubes often require both heating and cooling systems. The heaters at the cathodes vaporize mercury, while cool spots near the top of the tube condense it and return it to the pool. Some of these require almost a day to start up.
There was a large (about 3 feet tall) all glass mercury rectifier and several medium sized tubes in a lot of 100,000 tubes that I got about 12 years ago, but I gave them all away as soon as I found those.
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